On Wed, Aug 27, 2008 at 09:54:53AM -0400, Christoph Hellwig wrote:> On Tue, Aug 26, 2008 at 08:17:12PM -0400, Frank Ch. Eigler wrote:> > Among others, utrace is an enablement layer for systemtap user-space> > probing, through another subsequent part that implements a> > kprobes-like API for user-space tasks. All this code now exists in at> > least prototype form, so if you need to see the bigger picture, look> > that way. Other users are anticipated, but first we need to get past> > the chicken-and-egg.> > As usual nothing of that stuff has any real in-kernel users so the same> argument applies here. If it did have real uses it could be merged at> the same time. But the current uprobes mess is not a reason to merge> utrace.

Uprobes is just one user of utrace. It is intended for use for simpletracing where we need a kernel+userspace look at the problem at hand.The intention is for use in simple cases (when condition x is met, whatis the value of variable y, etc).

For more advanced tracing though, there are other ideas being proposed(see ntrace discussions on utrace-devel, but I guess now lkml is theright place for that discussion too).

However, there are components of uprobes such as breakpointinsertion/removal and single-stepping infrastructure that arepotentially useful to other userspace debuggers. We are working onfactoring those out to live independent of uprobes. You should be seeingthose patches soon.